This invention relates to a conoidal, rotating table solids separating system having a special spiral-like scraper. The separating system is for separating spherically-shaped rolling solids from irregularly-shaped nonrolling solids and is especially useful for oil shale retorting facilities using spherically-shaped heat carriers which are recovered and recycled through the retorting process.
There are many systems of separating solids which have significantly different particle sizes or particle weights, but there are relatively few dry, high capacity systems for efficiently separating solids having similar sizes and particle weights.
Copending Application Ser. No. 749,505, filed Dec. 10, 1976, which is entitled "Separation and Recovery of Heat Carriers in an Oil Shale Retorting Process", and which is owned by a common assignee and is incorporated herein, describes a conically-shaped rotating table separator for separating solids by differences in roll factor. The system is a dry, flexible, high capacity, efficient separating system. In this system, a mixture of spherically-shaped rolling solids and irregularly-shaped nonrolling solids is fed onto the table. The rolling solids roll off the table while the nonrolling solids come to rest on the table and move with the table until they are scraped off the table. These solids collect at the scraper and the operating characteristics of the table are partially affected by the design of the scraper. When the irregularly-shaped nonrolling solids come to rest on the table, they tend to trap rolling solids. The trapped rolling solids move with the irregularly-shaped solids and are either removed with these nonrolling solids or are removed at the same point as the nonrolling solids. In either case, the trapped rolling solids are disposed with the nonrolling solids unless other separating stages are used. This decreases the separating efficiency of the system.
This invention provides a special scraper arrangement for a conically-shaped table separator which causes release of trapped rolling solids and allows these solids to roll off the table at a point separate and apart from the point where the irregularly-shaped nonrolling solids are removed from the table.